U.S. Pat. No. 3,986,767 discloses an optical focus device having a plurality of housing sections for beam focusing means. The housing sections are movable by drive motors with respect to one another to rotate the beam about a plurality of orthogonal axes. The housing is mounted on a gantry for three dimensional movement of the device with respect to a workpiece. While the device includes housing parts relatively movable with respect to each other, such parts are not mounted to absorb shock when the device hits an obstruction.